1. Field of the Invention
The present invention relates to vehicle antennas and in particular to an antenna formed by a transparent coating laminated between two glass plies and an electrical connection arrangement for connecting the antenna to a radio or other transmitting/receiving device.
2. Technical Considerations
In the past, the traditional motor vehicle antenna for receiving and transmitting electromagnetic signals was a mast or whip-type antenna. Recently there has been a trend towards incorporating the antenna into the vehicle structure. For example, U.S. Pat. No. 3,987,449 to DeAngelis et al. discloses a wire antenna laminated within a vehicle windshield. U.S. Pat. No. 4,707,700 to Nagy positions an antenna within the roof structure of a vehicle. U.S. Pat. No. 5,416,491 to Nishikawa et al. forms antenna elements on a window using electroconductive ceramic paints. U.S. Pat. Nos. 4,768,037 and 4,849,766 to Inaba et al. and U.S. Pat. No. 5,355,144 to Walton et al. use a transparent electroconductive coating laminated between two glass plies to form an antenna. U.S. Pat. No. 5,083,135 to Nagy et al. utilizes a transparent coating in the form of a "T" to form an antenna. In each system, the connector arrangement conducts the signals received by the antenna to a receiver, for example a radio.
In order to feed the signals received by the antenna element to an external device, connectors, such as wires, braids or metal tabs, have been used. Problems arise when these elements are laminated within the transparency to make electrical contact with an antenna element. In particular, it has been found that when incorporating these types of connectors between the plies of the laminate, air may be entrapped in the laminate in the vicinity of the connector. It is believed that the connector hinders de-airing of the laminate during a conventional roll prepress operation. The bubbles formed by the entrapped air detract from the aesthetics of the window as well as increase the possibility of windshield delamination at or near the connector. U.S. Pat. No. 5,213,828 to Winter et al. addressed this problem in an electrically heatable windshield where electrical connection was required to be made to electroconductive elements within the windshield. A notch area was formed along the edge of the windshield and silver ceramic enamel leads from the windshield bus bar system were extended to the notch area where wires could then be soldered directly to the leads. However, it was found that during lamination, air would be forced through these porous enamel leads and into the laminate resulting in bubble formation near the notch area. To prevent this, prior to laminating, the ceramic leads were sealed, for example by filling the notch area with sealant. This prevented the bubble formation near the notch area of the laminate.
It would be advantageous to provide an antenna arrangement having a connector assembly that is positioned external to the laminate and electrically interconnects the antenna to an electromagnetic energy transmitting and/or receiving device and seals the connection area while maintaining the aesthetics of the window.